I’ve always said that a mechanic becomes a Master Mechanic when he or she makes his own tools. Some bike repair scenarios require very specific tools, and it’s impossible to press others into duty. In the brilliant Hard on Equipment, Corb Lund sings;

Well it’s vise grips for pliers /
And pliers for a wrench /
A wrench for a hammer /
Hammers everything else.

That’s just not going to cut it when you need to replace a headset. Which you actually would use a hammer for…

Bad example.

Seriously though, if you want to do it right, and not destroy the frame, you need a headset presses. Similarly, you need starnut setting tools, bottom bracket facing tools, cone wrenches, and truing stands.